PROJECT SUMMARY In Puerto Rico, the preterm birth rate is 17.7% of live births. At 50% above the U.S. average, it is the highest rate of any U.S. jurisdiction, below only Malawi (18.1%) globally. Puerto Rico also has 16 active Superfund sites and 200+ hazardous waste sites. Our investigations suggest that the increase in preterm birth rates in Puerto Rico cannot be explained by changes in obstetric practices and that there is sufficient evidence that exposure to hazardous chemicals contributes to preterm birth. Risk of exposure to contamination is high as many of these sites are unlined landfills that overlie karst aquifers. These aquifers present highly susceptible pathways for exposure to contamination and in fact there is extensive evidence of groundwater contamination. Established in 2010, the Puerto Rico Testsite for Exploring Contamination Threats Center (PROTECT) uses a holistic system of research, training and stakeholder engagement to study the fate, transport, exposure, health impact and remediation of contaminants, with particular attention to chlorinated solvents and phthalates commonly found at Superfund sites, as both suspect and model agents in the high preterm birth rates in Puerto Rico. PROTECT's new Community Engagement Core (Core F) will leverage the infrastructure and relationships developed in the center's first three years of funding through the Human Subjects and Sampling Core (Core C) and its research projects to serve as the main vehicle for interaction with community stakeholders in Puerto Rico. PROTECT's approach emphasizes bidirectional engagement with two groups of stakeholders: 1) women participating in the PROTECT study cohort (480 women as of March 2013); and 2) the broader group of residents in the areas where PROTECT's groundwater study is being conducted. Core C has established strong relationships with study participants as well as with service providers and a wide range of relevant community social actors, including staff and clinicians at community health centers and private clinics, social work and nursing staff, and community groups. Building on this foundation, Core F will develop a strong bidirectional communication strategy that will emphasize report-back of research findings to stakeholders, informed by stakeholders' priorities, needs and concerns. Core F will also focus on capacity-building for participants and their community organizations, and the development of resources for early childhood development through intervention supports for preterm children born to the participants. Core F activities will help provide appropriate ethical communication to participants via an innovative report-back process, enable participants to be more fully included in the research process, improve study recruitment and retention rates, offer lay perspectives and information, build capacity of participants and their community organizations, and lay the groundwork for additional community-based participatory research proposals.